Liquid crystal display devices are a most important display device used in recent multimedia society, and have been widely used from portable phones to computer monitors, laptops and televisions. As a liquid crystal display device, there is a TN mode in which a liquid crystal layer twist arranging nematic liquid crystals is placed between two orthogonal polarized plates, and an electric filed is applied in a direction perpendicular to a substrate. When a black color is displayed in such a TN mode type, double refraction caused by liquid crystal molecules occurs in an inclined viewing angle and light leakage occurs since liquid crystals are oriented in a direction perpendicular to a substrate.
In view of a viewing angle problem of such a TN mode type, an in-plane switching (IPS) mode in which two electrodes are formed on one substrate, and a liquid crystal director is controlled by a transverse electric field generated between the two electrodes has been introduced. In other words, the IPS mode type is also referred to as an in-plane switching liquid crystal display or a transverse electric field-type liquid crystal display, and by disposing electrodes in the same plane in a liquid crystal-disposed cell, the liquid crystals are lined up parallel to the transverse direction of the electrode instead of being lined up in a perpendicular direction.
In such a liquid crystal display device, an electrode and a wire line of a thin film transistor of each pixel are formed with metals, and due to high light reflectance resulted accordingly, it causes a problem of becoming an obstacle to the display screen.